`pog.transaction` and types | The Gleam Programming Language | Page 1

I tried using pog.transaction and it kind of confused me that the error type for the transaction is stringly typed. Here's my code:

type CreateError {
  UsernameAlreadyInUse
  WeakPassword
  CannotCreateUser
}

fn create_user(db, username, password) -> Result(_, CreateError) {
  use validated <- result.try(validate_password(password))
  use hashes <- result.try(hash_password(validated))
  case try_create_user(db, username, hashes) {
    Ok(_) -> Ok(...)
    Error(pog.TransactionRolledBack("UsernameAlreadyInUse")) ->
      Error(UsernameAlreadyInUse)
    Error(pog.TransactionRolledBack("CannotCreateUser") ->
      Error(CannotCreateUser)
    Error(pog.TransactionRolledBack(_)) ->
      panic as "unexpected rollback reason"
//  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Here I'm turning the string back in an error
  }
}

fn try_create_user(db, username, hashes) {
  use db <- pog.transaction(db)
  case sql.create_user(username, hashes.encoded_hash) {
    Error(pog.ConstraintViolation(..)) -> Error("UsernameAlreadyInUse")
    Error(_) -> Error("CannotCreateUser")
    //          ^^^^^^^^^^^^^^^^^^^^^^^^^ Error here must be a string!
    Ok(_) -> todo as "other queries in the same transaction..."
  }
}

create_user's result is later turned into a response I send back to the client. However, working with a transaction like this doesn't really feel great. Am I going about this completely wrong? Is this something others have brought up?

#`pog.transaction` and types